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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-3419 Detail

Description

Fastify incorrectly accepts malformed `Content-Type` headers containing trailing characters after the subtype token, in violation of RFC 9110 §8.3.1(https://httpwg.org/specs/rfc9110.html#field.content-type). For example, a request sent with Content-Type: application/json garbage passes validation and is processed normally, rather than being rejected with 415 Unsupported Media Type. When regex-based content-type parsers are in use (a documented Fastify feature), the malformed value is matched against registered parsers using the full string including the trailing garbage. This means a request with an invalid content-type may be routed to and processed by a parser it should never have reached. Impact: An attacker can send requests with RFC-invalid Content-Type headers that bypass validity checks, reach content-type parser matching, and be processed by the server. Requests that should be rejected at the validation stage are instead handled as if the content-type were valid. Workarounds: Deploy a WAF rule to protect against this Fix: The fix is available starting with v5.8.1.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cna.openjsf.org/security-advisories.html openjs
https://github.com/advisories/GHSA-573f-x89g-hqp9 openjs
https://github.com/fastify/fastify/commit/67f6c9b32cb3623d3c9470cc17ed830dd2f083d7 openjs
https://github.com/fastify/fastify/security/advisories/GHSA-573f-x89g-hqp9 openjs
https://httpwg.org/specs/rfc9110.html#field.content-type openjs
https://www.cve.org/CVERecord?id=CVE-2026-3419 openjs

Weakness Enumeration

CWE-ID CWE Name Source
CWE-185 Incorrect Regular Expression openjs  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-3419
NVD Published Date:
03/06/2026
NVD Last Modified:
03/06/2026
Source:
openjs